bin laden also hoped to kill general petraeus, commander of forces in afghanistan and soon to be cia director, the same way, either in a helicopter or fixed-wing airplane with a missile or rocket-propelled grenade. investigators do not believe the planning got very far. and both mr. obama and general petraeus have countermeasures on their aircrara and additional aircraft following them that would make them a very tough target, josh. >> chilling details. martha raddatz in washington, thank you. >>> secretary of state hillary clinton has arrived in turkey to meet with diplomats, hoping to end the 5-month-old conflict in libya. the u.s. has recognized the libya rebel group as the libya's legitimate government, freeing cash for weapons to take on moammar gadhafi's forces. >>> and roger clemens will learn in september whether he's off the hook for good. the judge in his federal perjury case declared a mistrial thursday after prosecutors showed jurors what was deemed inadmissssle evidence. clemens is charged with lying to congress about using performance-enhancing drugs. >>> and there's wo